One Scout lies on floor with a cup of water or something on their chest. A long rope has a small weight hanging down in the middle, two other scouts each hold an end of the rope (or it can be tied between two trees) and from a distance away try to swing the rope so that the weight knocks over the cup of water.
Blindfold Scouts if needed.
rope (one long piece and shorter bit, with weight at end, to hang from middle of longer section); cup; water
Similar to Two person skittles.